Great Falls dams handling significant run-off this season

Posted at 3:36 PM, May 18, 2018
and last updated 2018-07-05 14:56:25-04

GREAT FALLS – NorthWestern Energy Hydro Operations Director Jeremy Clotfelter says he loves to work with the historic sites around Great Falls.

“The thing that I love about all our hydro sites, a lot of them are very old they’re very historic. We have the opportunity to manage a facility that’s over 100 years old in some cases,” Clotfelter said.

NorthWestern Energy operates the five dams from Black Eagle to Morony Dam.

Clotfelter says this year’s significant run-off started a little later due to the high snow pack and cooler weather.

But only so much water can go through the plant at any given time.

“Here at Rainbow that is 8,000 cubic feet per second. For every cubic foot above 8,000, then we have to pass through or over the dam,” Clotfelter said.

Clotfelter says about 17,000 cubic feet per second is going over Rainbow Dam right now.

Per their operating license, whatever water that comes into Black Eagle they have to match the flows through the other dams leading all the way to Morony.

They are also able to control the elevation of the reservoirs and they are prepared for the water that is coming toward the dam.

“On a year like this they can fill completely and then the volume of Canyon Ferry will help keep our flows up after run off, through July, August, September, and October. It does give us some benefits, not today, but through the season,” Clotfelter said.

Clotfelter says they also keep an eye on the sticks and logs that are floating down the river.

There are two ways they deal with debris: one is the intake screens that feed into the power plant. They will rake the screen and dispose of the martial that is collected there.

The second is letting the debris go through the dam so it keeps going down stream.

“We have very experienced, very skilled crews that know how to deal with that. They do it quite often. If they have to take some extra care in getting something through they can certainly do it,” Clotfelter said.

There is only one place of concern when it comes to the high runoff this season.

“Where I think the real risk is on the river stretches and the valleys, where the normal river channel may not be able to handle the flow that is in the river. That is beyond our control,” Clotfelter said.